The previous post was more concerned with the geometry and the mathematically correct construction of the Wunderkreis in general.
Here is an example of how you can make it less theoretically. Denny Dyke from Circles in the Sand often creates double spirals and the Wunderkreis in his Dream Fields on the beach of Oregon. Denny Dyke has kindly shown me his method.
In the following photos it is explained.
Freehand he scratches the lines in the sand. Hence, the way runs between the lines. The double spiral has three arcs, the surrounding labyrinth has five circuits.
Denny begins with the lower part of the double spiral and draws three semicircles. On the left he adds two lines and the turning point, on the right there are three lines and the turning point (step 1).
Now he scratches three semicircles for the upper part of the double spiral. The first semicircle begins in the middle of the innermost lower semicircle (step 2).
All the other curves are drawn in parallel and equal distance to this arc by connecting all free ends of the existing lines and the turning points. Just the way we do it in the Classical labyrinth. We begin on top and draw four lines on the left side around the double spiral to the right side (step 3).
In the same way the two free lines below are connected together (step 4). Having done this the Wunderkreis has quite been completed.
The open lower middle section contains the two entries of the Wunderkreis. On the left side we enter the labyrinthine circuits. On the right side we have the exit out of the double spiral.
Denny has marked both accesses and has separated them through the “shoehorn” known from the Baltic wheel.